I don't have an iPhone but since the conversion of my .mac account to mobileme my MacPro 8 core 'supercomputer' locks up each time I access iDisk to update my kids' band website. I have to kill the power to restart it! Yikes! In case you haven't seen it ...
http://web.mac.com/theberrysband
But, they did give me an extra month subscription for free. An extra month of faulty service! Go figure.
Still, I wouldn't use a PC if you paid me. I only use them at work because they do.